Whitby Power Brake Frame Mod

[Norm B]

I am converting to power brakes and ordered the frame mod from Whitby a month ago and haven't got the part yet. Anyone have the directions where to cut the frame to instal the frame mod. I am almost to the point of fitting up the booster but need to cut the frame and only want to do that once.

Thanks

Norm

[michael everson]

You could just skip the Whitby piece and do what I do.
Cut the frame at 1 inch from the foot box and at 6 inches. Then buy another piece of tube that is 8 inches long and bolt it to the outside of the section you just cut out. Works perfect.
mike


https://farm1.staticflickr.com/815/41374543341_b0e72ee65b_z.jpg

https://farm1.staticflickr.com/889/41374543821_6548151e24_z.jpg

[Jeff Kleiner]

I do the same as Mike. Don't forget to space the booster 3/8" forward of the front wall of the footbox.

Jeff

[wibby]

I looked at mine, but there is no way to get a good pic, or measurement of the cut closest to the foot box on my finished car. It might be best to give Jeff a call at Whitby.

[edwardb]

This is what the frame mod looked like on the Mk3 I had a few years ago. Pretty easy to see where it's cut.

http://i867.photobucket.com/albums/ab234/edwardb123/Factory%20Five%20Mark%203%20Roadster%20Build/Brakes/IMG_1029.jpg (http://s867.photobucket.com/user/edwardb123/media/Factory%20Five%20Mark%203%20Roadster%20Build/Brakes/IMG_1029.jpg.html)

To Mike and Jeff's point, it does clear the booster by a lot.

http://i867.photobucket.com/albums/ab234/edwardb123/Factory%20Five%20Mark%203%20Roadster%20Build/Brakes/IMG_1035%202_zpscjhicrqm.jpg (http://s867.photobucket.com/user/edwardb123/media/Factory%20Five%20Mark%203%20Roadster%20Build/Brakes/IMG_1035%202_zpscjhicrqm.jpg.html)

[Norm B]

Thanks for the replies. I'll do as Mike and Jeff suggested.

Jeff, I made a spacer out of 1/2 inch aluminum plate. That is what my measurements said I needed with my combination of a 95 pedal box and an 87 booster.

For anyone contemplating power brakes, do it before the body is on! After is about as much fun as a root canal without anesthetic.

Norm

[DadofThree]

Perhaps I can help. These are posts while I was trying to blog the build.

Measuring
http://buildacobra.blogspot.com/2015/12/power-brakes-arrived.html?m=1

Day 1 of install
http://buildacobra.blogspot.com/2015/12/started-power-brake-mod.html?m=1

Day 2 of install
http://buildacobra.blogspot.com/2015/12/whitby-power-brake-nightmare-cont.html?m=1

[JRL16]

I would recommend waiting for the mod till you have the part so you can get an exact cut. Also Replica Parts has a spacer that helps to seal the rubber on the back of the booster instead of just making a spacer. The booster directions call for 3/8” but the spacer they sold me was 1/2”. Called them and they said it was fine but after trying it out the pedal was too close to the footbox wall and needed to be moved toward the driver. I milled the spacer down to 5/16” and that gave the pedal a nice resting position more inline with the clutch pedal and still not making contact with the 3/4” tube welded in by FFR to keep the pedal from moving forward. Good luck.

[Kpt112]

Does anyone know what master cylinder and brake booster Whitby's is selling? I mean what car is it actually from? Just curious.

[John Dol]

Instead of cutting the bar out, you can actually just cut a section out of the bar. Invert it and weld it back in. That way you don't have that odd looking jog in the bar.
Worked on my Coupe.

John

[John Dol]

84035

[Norm B]

I called Jeff at Whitby and they had not processed the order yet so I canceled it. I went with the mod suggested by Mike. Everything fits nicely. With todays weather I am thinking I should be building some sort of a snow machine.

[Norm B]

Power brake mod completed. Took the car for a drive and the brakes are great. It can be done with the body on but, changing the pedal is a challenge!

Norm